Some patients for whom medication is provided in the form of pills, because of their poor medical conditions, have difficulty in swallowing the pills. It has therefore previously been proposed to provide a pill crusher, by means of which pills can be crushed into a powder form. The powder produced in this way can then be added to a liquid to provide a mixture which is more easily consumable by such patients.
In most healthcare facilities, crushing pills for patients is a frequently performed task. At the present time, pills are usually crushed by employing a manual pill crusher, but this frequently results in the manual exertion of high forces, or postures and repetitive movements that can contribute to injuries of the hands, wrists and shoulders. Furthermore, inhalation of airborne dust, which occurs during the crushing process, has also been reported to be a problem.
To reduce the magnitude of the forces required to crush pills, manufacturers of manual pill crushers have designed lever-type mechanical devices employing a metal head attached to a lever arm which pivots about a fulcrum.
However, even with the use of such lever-type mechanical devices, the forces required are often still high, and the users are still required to assume awkward postures and to perform repetitive movements. Awkward postures of the shoulder occur because pill crushers are typically placed on the tops of medication carts and the heights of the top surfaces of the medication carts are usually too high for most workers. The design of a typical lever-type crusher is such that downward forces are required to be exerted on a straight handle, which results in awkward postures of the wrist.
Examples of prior manually actuated pill crushers are disclosed, for example, in U.S. Pat. Nos. 2,631,786; 3,915,393; 6,059,209 and 6,357,679.
In U.S. Pat. No. 6,508,424 there is disclosed a battery operated pill crusher comprising a cylindrical plunger which can be moved downwardly into a cylindrical container, the bottom of which is in the form of a turntable which can be rotated by an electric motor and which has an upper surface formed with a plurality of grinding protrusions. In use of this prior device, a pill is inserted between the upper surface of the turntable and the plunger, the plunger is pressed downwardly and the turntable is then rotated, so that rotational motion as well as compression is applied to the pill, which is thereby pulverized. However, this prior device has the disadvantage that it is necessary to press the plunger down manually toward the turntable, which is resiliently mounted, so that the crushing forces which can be exerted on the pill are limited. Another disadvantage of this prior device is the risk that rotation of the turntable could be initiated by pressing directly onto the turntable with, for example, a finger, while the plunger is removed.
Canadian Patent Number 2,057,245 discloses a pill crusher and grinder for use especially in nursing homes and domestic environments, the pill crusher and grinder having a pill or tablet-receiving and holding means, a rotary crushing and grinding means having a rotary shaft, a tablet contacting element on one end of the shaft and rotatable therewith and means for rotating the shaft. In a preferred embodiment, the shaft is adapted firstly to break the tablet into small pieces and then to crush and grind it by rotary action within the pill receiving and holding means. The means for rotating the shaft is a manually operable handle. The rotary shaft is screw-threaded and is received in a complementary screw-threaded receiver, which is fixed with respect to the tablet receiving and holding means. However, this prior device has the disadvantage that it employs rotary blades, which can pose a safety hazard.
In U.S. Pat. No. 5,067,666 there is disclosed a battery operated pill crusher comprising a selectively activatable motor to produce a power source to a cam-driven ram which reciprocates once on a vertical axis into and out of engagement with a pill in a medication cup with sufficient force to “smash” the pill. The ram is returned to its uppermost position by the coaction of the eccentric cam and a compression spring operatively circumscribed thereabout. However, this prior device has the disadvantage that the ram does not rotate while being displaced, so that the crushing abilities which can be exerted on the pill are limited. Another disadvantage of this prior device is the use of a compression spring to retract the plunger, which may weaken its ability to retract the plunger over time.